This invention relates generally to machines and processes for rejuvenating crushed asphalt removed, as with a milling machine, from a previously paved surface, and for recycling such rejuvenated asphalt back to the same surface from which it was removed or, otherwise, back to another prepared surface.
Vehicle for removing said reclaiming asphalt from a previously paved surface and returning same to the surface from which it was taken are, generally speaking, well known in the prior art. See, for example, U.S. Pat. No. 3,843,274 issued to Nathan Gutman, et al. on Oct. 22, 1974 entitled "Asphalt Reclaimer" wherein a machine employing a means for heating the upper layer of asphalt, a rotary cutter for lifting the heated asphalt, a pugmill for pulverizing the lifted asphalt, a spreader for redistributing the pulverized asphalt and a leveler is disclosed. This apparatus employs a propane gas storage tank to supply fuel to a series of heaters including an infra red heater to heat the road surface immediately prior to removal of asphalt with the rotary cutter, a heater to heat the pugmill, and a heater associated with a vibrator type of spreading means.
See also U.S. Pat. No. 4,011,023 issued to Earl F. Cutter on Mar. 8, 1977 on "Asphalt Paving Recycling Apparatus" which discloses a machine for removing crumbled pavement from a roadway, which machine contains a heater for preliminarily heating the crumbled material removed from a pavement, another heater for heating liquid asphalt being added to the crumbled material and a series of radiant heaters for raising the temperature of the crumbled material and asphalt mix to lower its viscosity. Additional roadbed heaters are also employed to raise the temperature of the roadbed site upon which the recycled asphalt is to be applied.
See also U.S. Pat. No. 2,394,017 issued to H. J. Seaman on Feb. 5, 1946 entitled "Road Building Machine" which discloses an apparatus for gathering asphalt from a roadway, a burner for passing over the loosened surface material for heating the same, a mixer for throwing the material against the walls of the mixing chamber to pulverize the same, and a sprayer for adding a liquid binder to the pulverized material.
One difficulty that has been encountered using such prior art asphalt recycling machines and methods is the necessity of providing expensive fuel for the various heaters and burners employed to raise the temperature of the crumbled asphalt. This difficulty is compounded by the increasing cost and scarcity of such fuels under present day conditions.
Moreover, the processes employed by these prior art machines merely add asphalt oils back to the crumbled material as a binder to restore the bondable nature of the asphalt which has been lost due to the volatilization or evaporation of the oil originally contained in the asphalt when originally laid.
By means of the machine and process of our invention, we substantially overcome these and other difficulties encountered in the prior art.